<!--
 * @Author: your name
 * @Date: 2021-08-05 16:37:04
 * @LastEditTime: 2021-08-05 18:37:47
 * @LastEditors: Please set LastEditors
 * @Description: In User Settings Edit
 * @FilePath: \briup\3-html&css\day04\3-id选择器.html
-->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>id选择器</title>
    <style>
       #app {
               height:200px;
       }
       .myDiv {
           color:orange;
       }
       #one {
           border: 1px solid greenyellow;
       }
    </style>
</head>
<body>
    <div id="app">
        
        <div class="myDiv" id="one">1</div>
        <div class="myDiv" id="two">2</div>
        <div class="myDiv" id="three">3</div>
    </div>
</body>
</html>